#include<stdio.h>
int main()
{
    int a,i,m;
    printf ("There are following perfect numbers smaller than 1000:\n");
    for (a=1; a<1000; a++)
    {
        for(m=0, m=1;i<=a/2;i++)
            if(!(a%i))m+=i;
            if(m==a)
            printf("%4d",a);
    }
}

//吴昌源
